/*
 * Copyright (c) 2022 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import isValidNumber from '../validate_.js'
import parseDigits from '../helpers/parseDigits.js'

import {
	startsWith,
	endsWith
} from './util.js'

/**
 * Leniency when finding potential phone numbers in text segments
 * The levels here are ordered in increasing strictness.
 */
export default
{
	/**
	 * Phone numbers accepted are "possible", but not necessarily "valid".
	 */
	POSSIBLE(number, candidate, metadata)
	{
		return true
	},

	/**
	 * Phone numbers accepted are "possible" and "valid".
	 * Numbers written in national format must have their national-prefix
	 * present if it is usually written for a number of this type.
	 */
	VALID(number, candidate, metadata)
	{
		if (!isValidNumber(number, undefined, metadata) ||
			!containsOnlyValidXChars(number, candidate.toString(), metadata))
		{
			return false
		}

    // Skipped for simplicity.
		// return isNationalPrefixPresentIfRequired(number, metadata)
    return true
  },

	/**
	 * Phone numbers accepted are "valid" and
	 * are grouped in a possible way for this locale. For example, a US number written as
	 * "65 02 53 00 00" and "650253 0000" are not accepted at this leniency level, whereas
	 * "650 253 0000", "650 2530000" or "6502530000" are.
	 * Numbers with more than one '/' symbol in the national significant number
	 * are also dropped at this level.
	 *
	 * Warning: This level might result in lower coverage especially for regions outside of
	 * country code "+1". If you are not sure about which level to use,
	 * email the discussion group libphonenumber-discuss@googlegroups.com.
	 */
	STRICT_GROUPING(number, candidate, metadata, regExpCache)
	{
		const candidateString = candidate.toString()

		if (!isValidNumber(number, undefined, metadata)
			|| !containsOnlyValidXChars(number, candidateString, metadata)
			|| containsMoreThanOneSlashInNationalNumber(number, candidateString)
			|| !isNationalPrefixPresentIfRequired(number, metadata))
		{
			return false
		}

		return checkNumberGroupingIsValid
		(
			number,
			candidate,
			metadata,
			allNumberGroupsRemainGrouped,
			regExpCache
		)
  },

	/**
	 * Phone numbers accepted are {@linkplain PhoneNumberUtil#isValidNumber(PhoneNumber) valid} and
	 * are grouped in the same way that we would have formatted it, or as a single block. For
	 * example, a US number written as "650 2530000" is not accepted at this leniency level, whereas
	 * "650 253 0000" or "6502530000" are.
	 * Numbers with more than one '/' symbol are also dropped at this level.
	 * <p>
	 * Warning: This level might result in lower coverage especially for regions outside of country
	 * code "+1". If you are not sure about which level to use, email the discussion group
	 * libphonenumber-discuss@googlegroups.com.
	 */
	EXACT_GROUPING(number, candidate, metadata, regExpCache)
	{
		const candidateString = candidate.toString()

		if (!isValidNumber(number, undefined, metadata)
			|| !containsOnlyValidXChars(number, candidateString, metadata)
			|| containsMoreThanOneSlashInNationalNumber(number, candidateString)
			|| !isNationalPrefixPresentIfRequired(number, metadata))
		{
			return false
		}

		return checkNumberGroupingIsValid
		(
			number,
			candidate,
			metadata,
			allNumberGroupsAreExactlyPresent,
			regExpCache
		)
	}
}

function containsOnlyValidXChars(number, candidate, metadata)
{
  // The characters 'x' and 'X' can be (1) a carrier code, in which case they always precede the
  // national significant number or (2) an extension sign, in which case they always precede the
  // extension number. We assume a carrier code is more than 1 digit, so the first case has to
  // have more than 1 consecutive 'x' or 'X', whereas the second case can only have exactly 1 'x'
  // or 'X'. We ignore the character if it appears as the last character of the string.
  for (let index = 0; index < candidate.length - 1; index++)
  {
    const charAtIndex = candidate.charAt(index)

    if (charAtIndex === 'x' || charAtIndex === 'X')
    {
      const charAtNextIndex = candidate.charAt(index + 1)

      if (charAtNextIndex === 'x' || charAtNextIndex === 'X')
      {
        // This is the carrier code case, in which the 'X's always precede the national
        // significant number.
        index++
        if (util.isNumberMatch(number, candidate.substring(index)) != MatchType.NSN_MATCH)
        {
          return false
        }
	      // This is the extension sign case, in which the 'x' or 'X' should always precede the
	      // extension number.
      }
      else if (parseDigits(candidate.substring(index)) !== number.ext)
      {
        return false
      }
    }
  }

  return true
}

function isNationalPrefixPresentIfRequired(number, _metadata)
{
  // First, check how we deduced the country code. If it was written in international format, then
  // the national prefix is not required.
  if (number.getCountryCodeSource() != 'FROM_DEFAULT_COUNTRY')
  {
    return true
  }

  const phoneNumberRegion = util.getRegionCodeForCountryCode(number.getCountryCode())

  const metadata = util.getMetadataForRegion(phoneNumberRegion)
  if (metadata == null)
  {
    return true
  }

  // Check if a national prefix should be present when formatting this number.
  const nationalNumber = util.getNationalSignificantNumber(number)
  const formatRule = util.chooseFormattingPatternForNumber(metadata.numberFormats(), nationalNumber)

  // To do this, we check that a national prefix formatting rule was present
  // and that it wasn't just the first-group symbol ($1) with punctuation.
  if (formatRule && formatRule.getNationalPrefixFormattingRule().length > 0)
  {
    if (formatRule.getNationalPrefixOptionalWhenFormatting())
    {
      // The national-prefix is optional in these cases, so we don't need to check if it was
      // present.
      return true
    }

    if (PhoneNumberUtil.formattingRuleHasFirstGroupOnly(
        formatRule.getNationalPrefixFormattingRule()))
    {
      // National Prefix not needed for this number.
      return true
    }

    // Normalize the remainder.
    const rawInputCopy = PhoneNumberUtil.normalizeDigitsOnly(number.getRawInput())

    // Check if we found a national prefix and/or carrier code at the start of the raw input, and
    // return the result.
    return util.maybeStripNationalPrefixAndCarrierCode(rawInputCopy, metadata, null)
  }

  return true
}

export function containsMoreThanOneSlashInNationalNumber(number, candidate)
{
  const firstSlashInBodyIndex = candidate.indexOf('/')
  if (firstSlashInBodyIndex < 0)
  {
    // No slashes, this is okay.
    return false
  }

  // Now look for a second one.
  const secondSlashInBodyIndex = candidate.indexOf('/', firstSlashInBodyIndex + 1)
  if (secondSlashInBodyIndex < 0)
  {
    // Only one slash, this is okay.
    return false
  }

  // If the first slash is after the country calling code, this is permitted.
  const candidateHasCountryCode =
      (number.getCountryCodeSource() === CountryCodeSource.FROM_NUMBER_WITH_PLUS_SIGN
       || number.getCountryCodeSource() === CountryCodeSource.FROM_NUMBER_WITHOUT_PLUS_SIGN)

  if (candidateHasCountryCode
      && PhoneNumberUtil.normalizeDigitsOnly(candidate.substring(0, firstSlashInBodyIndex))
          === String(number.getCountryCode()))
  {
    // Any more slashes and this is illegal.
    return candidate.slice(secondSlashInBodyIndex + 1).indexOf('/') >= 0
  }

  return true
}

function checkNumberGroupingIsValid(
  number,
  candidate,
  metadata,
  checkGroups,
  regExpCache
) {
  const normalizedCandidate = normalizeDigits(candidate, true /* keep non-digits */)
  let formattedNumberGroups = getNationalNumberGroups(metadata, number, null)
  if (checkGroups(metadata, number, normalizedCandidate, formattedNumberGroups)) {
    return true
  }

  // If this didn't pass, see if there are any alternate formats that match, and try them instead.
  const alternateFormats = MetadataManager.getAlternateFormatsForCountry(number.getCountryCode())
  const nationalSignificantNumber = util.getNationalSignificantNumber(number)

  if (alternateFormats) {
    for (const alternateFormat of alternateFormats.numberFormats()) {
      if (alternateFormat.leadingDigitsPatterns().length > 0) {
        // There is only one leading digits pattern for alternate formats.
        const leadingDigitsRegExp = regExpCache.getPatternForRegExp('^' + alternateFormat.leadingDigitsPatterns()[0])
        if (!leadingDigitsRegExp.test(nationalSignificantNumber)) {
          // Leading digits don't match; try another one.
          continue
        }
      }
      formattedNumberGroups = getNationalNumberGroups(metadata, number, alternateFormat)
      if (checkGroups(metadata, number, normalizedCandidate, formattedNumberGroups)) {
        return true
      }
    }
  }

  return false
}

/**
 * Helper method to get the national-number part of a number, formatted without any national
 * prefix, and return it as a set of digit blocks that would be formatted together following
 * standard formatting rules.
 */
function getNationalNumberGroups(
	metadata,
	number,
	formattingPattern
) {
  if (formattingPattern) {
    // We format the NSN only, and split that according to the separator.
    const nationalSignificantNumber = util.getNationalSignificantNumber(number)
    return util.formatNsnUsingPattern(nationalSignificantNumber,
                                      formattingPattern, 'RFC3966', metadata).split('-')
	}

  // This will be in the format +CC-DG1-DG2-DGX;ext=EXT where DG1..DGX represents groups of digits.
  const rfc3966Format = formatNumber(number, 'RFC3966', metadata)

  // We remove the extension part from the formatted string before splitting it into different
  // groups.
  let endIndex = rfc3966Format.indexOf(';')
  if (endIndex < 0) {
    endIndex = rfc3966Format.length
  }

  // The country-code will have a '-' following it.
  const startIndex = rfc3966Format.indexOf('-') + 1
  return rfc3966Format.slice(startIndex, endIndex).split('-')
}

function allNumberGroupsAreExactlyPresent
(
	metadata,
	number,
	normalizedCandidate,
	formattedNumberGroups
)
{
  const candidateGroups = normalizedCandidate.split(NON_DIGITS_PATTERN)

  // Set this to the last group, skipping it if the number has an extension.
  let candidateNumberGroupIndex =
      number.hasExtension() ? candidateGroups.length - 2 : candidateGroups.length - 1

  // First we check if the national significant number is formatted as a block.
  // We use contains and not equals, since the national significant number may be present with
  // a prefix such as a national number prefix, or the country code itself.
  if (candidateGroups.length == 1
      || candidateGroups[candidateNumberGroupIndex].contains(
          util.getNationalSignificantNumber(number)))
  {
    return true
  }

  // Starting from the end, go through in reverse, excluding the first group, and check the
  // candidate and number groups are the same.
  let formattedNumberGroupIndex = (formattedNumberGroups.length - 1)
  while (formattedNumberGroupIndex > 0 && candidateNumberGroupIndex >= 0)
  {
    if (candidateGroups[candidateNumberGroupIndex] !== formattedNumberGroups[formattedNumberGroupIndex])
    {
      return false
    }
    formattedNumberGroupIndex--
    candidateNumberGroupIndex--
  }

  // Now check the first group. There may be a national prefix at the start, so we only check
  // that the candidate group ends with the formatted number group.
  return (candidateNumberGroupIndex >= 0
      && endsWith(candidateGroups[candidateNumberGroupIndex], formattedNumberGroups[0]))
}


function allNumberGroupsRemainGrouped
(
	metadata,
	number,
	normalizedCandidate,
	formattedNumberGroups
)
{
  let fromIndex = 0
  if (number.getCountryCodeSource() !== CountryCodeSource.FROM_DEFAULT_COUNTRY)
  {
    // First skip the country code if the normalized candidate contained it.
    const countryCode = String(number.getCountryCode())
    fromIndex = normalizedCandidate.indexOf(countryCode) + countryCode.length()
  }

  // Check each group of consecutive digits are not broken into separate groupings in the
  // {@code normalizedCandidate} string.
  for (let i = 0; i < formattedNumberGroups.length; i++)
  {
    // Fails if the substring of {@code normalizedCandidate} starting from {@code fromIndex}
    // doesn't contain the consecutive digits in formattedNumberGroups[i].
    fromIndex = normalizedCandidate.indexOf(formattedNumberGroups[i], fromIndex)
    if (fromIndex < 0) {
      return false
    }
    // Moves {@code fromIndex} forward.
    fromIndex += formattedNumberGroups[i].length()
    if (i == 0 && fromIndex < normalizedCandidate.length())
    {
      // We are at the position right after the NDC. We get the region used for formatting
      // information based on the country code in the phone number, rather than the number itself,
      // as we do not need to distinguish between different countries with the same country
      // calling code and this is faster.
      const region = util.getRegionCodeForCountryCode(number.getCountryCode())
      if (util.getNddPrefixForRegion(region, true) != null
          && Character.isDigit(normalizedCandidate.charAt(fromIndex))) {
        // This means there is no formatting symbol after the NDC. In this case, we only
        // accept the number if there is no formatting symbol at all in the number, except
        // for extensions. This is only important for countries with national prefixes.
        const nationalSignificantNumber = util.getNationalSignificantNumber(number)
        return startsWith
        (
      	  normalizedCandidate.slice(fromIndex - formattedNumberGroups[i].length),
           nationalSignificantNumber
        )
      }
    }
  }

  // The check here makes sure that we haven't mistakenly already used the extension to
  // match the last group of the subscriber number. Note the extension cannot have
  // formatting in-between digits.
  return normalizedCandidate.slice(fromIndex).contains(number.getExtension())
}